Mercaptobenzothiazole MBT

MBT is one of the early rubber accelerators discovered in the 1920s. It is not used nearly as much as its chemical cousin MBTS. 

Methane Sulfur Carbon Disulfide Hydrogen Sulfide 

Lanxess Kawaguchi General Quimica R. T. Vanderbilt Prochimie Acna Landaise Ouchi Shinko 

Changde Dingyuan Chemical Industrial Limited Qingzhou Kunwei Industry and Trade Co., Ltd. 

Zhengzhou Double Vigour Chemical Product Co., Ltd. Dongying Bochen Chemical CLP PVI Co., Ltd. 

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Mercaptobenzothiazoles. These compounds form the basis for the largest-volume organic accelerators. 2-Mercaptobenzothiazole (MBT)... 

The thiophthalimide (CTP) and sulfenamide classes of retarders differ from the organic acid types by thek abiUty to retard scorch (onset of vulcanization) without significantly affecting cure rate or performance properties. Much has been pubUshed on the mechanism of CTP retardation. It functions particularly well with sulfenamide-accelerated diene polymers, typically those used in the the industry. During the initial stages of vulcanization, sulfenamides decompose to form mercaptobenzothiazole (MBT) and an amine. The MBT formed reacts with additional sulfenamide to complete the vulcanization process. If the MBT initially formed is removed as soon as it forms, vulcanization does not occur. It is the role of CTP to remove MBT as it forms. The retardation effect is linear with CTP concentration and allows for excellent control of scorch behavior. 

Cure Characteristics. Methods of natural rubber production and raw material properties vary from factory to factory and area to area. Consequentiy, the cure characteristics of natural mbber can vary, even within a particular grade. Factors such as maturation, method and pH of coagulation, preservatives, dry mbber content and viscosity-stabilizing agents, eg, hydroxylamine-neutral sulfate, influence the cure characteristics of natural mbber. Therefore the consistency of cure for different grades of mbber is determined from compounds mixed to the ACSl formulation (27). The ACSl formulation is as follows natural mbber, 100 stearic acid, 0.5 zinc oxide, 6.0 sulfur, 3.5 and 2-mercaptobenzothiazole (MBT), 0.5. 

Mercieca MD, Rodwell DE, Hinderer RK, et al Mercaptobenzothiazole (MBT) A two-generation study using Sprague-Dawley rats. Toxicologst 11(1) 112, 1991... 

Sorahan, T. Pope, D. (1993) Mortality study of workers employed at a plant manufacturing chemicals for the rubber industry 1955-86. Br. J. ind. Med., 50, 998-1002 Sorahan, T., Hamilton, L. Jackson, J.R. (2000) A further cohort study of workers employed at a factory manufacturing chemicals for the rubber industry, with special reference to the chemicals 2-mercaptobenzothiazole (MBT), aniline, phenyl-beta-naphthylamine and o-toluidine. Occup. environ. Med., 57, 106-115... 

Sodium mercaptobenzothiazole (MBT) is seldom used today due to its susceptibility to breakdown by chlorine. 

Barnes et al developed an LC-MS method to identify vulcanisation agents and their breakdown products in food and drink samples. A large sample of 236 retail foodstuffs were analysed for the presence of 2-mercaptobenzothiazole (MBT) and its breakdown product mercapto-benzothiazole (MB). The accelerators 2-mercaptobenzothiazyl (MBTS) and A-cyclohexyl-2-benzothiazole sulphenamide (CBS), which are commonly used in food contact rubbers, were also looked for. MBT and MB are also known to be breakdown products of these two compounds. The detection limit for these species was found to depend on the food product type and ranged from 0.005-0.043 mg/kg. No MBT, MB, MBTS or CBS were detected in any of the samples above these levels. 

Accelerators are chemical compounds that iacrease the rate of cure and improve the physical properties of the compound. As a class, they are as important as the vulcanising agent itself Without the accelerator, curing requires hours or even days to achieve acceptable levels. Aldehyde amines, thiocarbamates, thiuram sulfides, guanidines, and thiasoles are all classified as accelerators. By far, the most widely used are the thiazoles, represented by mercaptobenzothiazole (MBT and benzothiazyl disulfide (MBTS). 

In 1921, C. W. Bedford, at Rubber Services Laboratories Co., L. B. Sebrell, for Goodyear Tyre Rubber, both in the US, and Bruni and Romani at Pirelli, in Italy, developed mercaptobenzothiazole (MBT) (97) as an organic accelerator. In 1931, Bayer converted mercaptobenzothiazole into sulfenamides, that contain the grouping =CSNR2. These later became the most important class of accelerators. 

The vulcanization accelerators include the thiazole 2-mercaptobenzothiazole (MBT) (169), and its derivative benzothiazole disulfide (dibenzoythiazyl disulfide, 2,2 -dithiobis (benzothiazole), MBTS) (170). Organic accelerators enable reduction in time of vulcanization, more effective use of sulfur in formation of cross-links and use of low processing temperatures. MBTS delays vulcanization, when compared with MBT alone. They are used in production of conveyor belts, footware, etc. The 2-mercaptobenzothiazole zinc salt (MBTZ) (171) is also important, and is used in latex products. Other sulfur donors include 2-morpholinodithiobenzothiazole, 2-(4-morpholinyldithio)benzothiazole (MBSS, MORFAX) (172). 

We have developed a new patented catalytic oxygen based coupling route which not only eliminates the salt by-products (the only by-product is water), but allows us to directly couple mercaptobenzothiazole (MBT) direcdy with the desired primary or secondary amine in a quantitative yield under very mild conditions room temperature to 70 C tinder ambient to 50 psig O2, and the reaction times are short (< 1 hr). The activated carbon catalysts, described earlier for the production of the herbicide active glyphosate, are extremely efficient catalysts for this transformation. The only waste product in this reaction is water ... 

Base compound NR (pale creep) 100 sulfur 3 mercaptobenzothiazole (MBT) 0.5. Temperature of vulcanization 142°C. 

A typical vulcanization system for EPDM rubber consists of 1.5 parts sulfur, 5.0 parts zinc oxide, 1.0 part stearic acid, 1.5 parts 2-mercaptobenzothiazole (MBT), and 0.5 part tetramethylthiuram disulbde (TMTD) per 100 parts polymer. 

One of the main applications for cyclohexylamine is in the manufacture of the vulcanization accelerator, cyclohexylbenzothiazolesulfenamide (CBS) from cyclohexylamine and 2-mercaptobenzothiazole (MBT). The dicyclohexylamine derivative is also used as a vulcanization accelerator (DCBS). 

The object of our study was acrylonitrile-butadiene rubber PERBUNAN 2845 F (LANXESS), acrylonitrile content 28%. Two types of carbon black were used Colour Black FW 200 (Evonik Degussa GMbH) and FEF N550 (Evonik Degussa GMbH). The elastomer was crosslinked by sulphur vulcanization system. The following compounds were used as accelerators mercaptobenzothiazole (MBT) and... 

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